Topic（题目）：Study of the two-proton radioactivity within the Gamow coupled-channel approach
Speaker（报告人）：Simin wang (Michigan State University)
Date（时间）： 2019年6月18号（周二）下午4:00-5:30
Place（地点）： 北京大学加速器楼424 会议室
Contact Person（联系人）：许甫荣（frxu@pku.edu.cn）
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Abstract:
Background Two-proton (2p) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The 2pdecay width and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. For example, in mid-heavy nuclei, the measured 2pdecay of67Kr turned out to be unexpectedly fast [1]. And more recently, as the mirror of the halo nucleus11Li,11O was observed for the first time with a very broad peak [2].
Purpose In the present work, we investigate the role of deformation and continuum effect in the structure and decay properties of67Kr and11;12O, as well as the Thomas-Ehrman effect between11;12O and their respective bound mirror nuclei.MethodsTo understand these exotic phenomena, we apply the newly developed Gamow coupled-channel (GCC) method [3], which describes structure and decays of three-body systems within one coherent theoretical framework by utilizing resonant and scattering states in eigenfunction expansion.
Results For mid-heavy nuclei, we analyzed the 2pdecay lifetime and angular correlations of48Ni and67Kr with respect to different deformations and interactions; for light nuclei, we calculated the energy spectra and decay widths of11O and12O as well as those of their mirror nuclei. In particular, we investigate the dynamics of the 2pdecay in the ground state of12O (versus6Be) by analyzing the evolution of the 2pconfiguration of the emitted protons as well as their angular correlation. We also provide insight on the role of the underlying structure of theA-1 subsystems in the 2pdecay of11O and12O.
Conclusions We show that deformation couplings significantly increase the 2pdecay width of67Kr; this finding explains the puzzling experimental data. For light nuclei, with GCC approach, the broad structure observed in11O appears as a multiplet, with the possible 3/21-ground state strongly influenced by the broad threshold resonant state in10N, which is an isobaric analog of the virtual state in10Li. And a moderate isospin asymmetry between11;12O and their mirror nuclei was found.
1. T. Goigoux et al., Phys. Rev. Lett. 117, 162501 (2016).
2. T.B. Webb et al., arXiv:1812.08880.
3. S.M. Wang and W. Nazarewicz, Phys. Rev. Lett. 120, 212502 (2018)
Biography:
The speaker, Simin Wang, is a research associate working in national superconducting cyclotron laboratory, Michigan State University. His research is mainly focus on the theoretical nuclear physics, especially, on the open quantum systems, two-proton decay, and halo nuclei near the dripline. Such systems offer valuable opportunities to study the continuum effect on the nuclear structure and reaction.
